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Built-in lock
Each java object can be used as a synchronization lock to achieve, these locks are called built-in lock. When a thread enters a synchronized block or method of automatically acquire the lock, when you exit the synchronized block or method will release the lock. The only way to get the lock is built into this code block or method with fuzzy protected lock.
Mutex
Built-in lock is a mutex, which is meant at most only one thread can acquire the lock when thread A thread B attempts to get hold of the built-in lock, thread A must wait or block until the thread B releases the lock, If the thread does not release the lock B, then A thread will wait forever.
Modification of the conventional method: Example locked object
Modification of the conventional method: lock the entire class
Modifying the code block: synchronized lock to lock an object (Lock) i.e. synchronized parentheses after the contents
